Usually always have a spare on the charger. When ProVari starts blinking I swap it out. Anytime I leave the house I swap for a fully charged batt, top off the 3.5mL Vision and I good to go for several hours. I don't like messin with nuttin, and don't have a lot of variability in my vapin. Don't have to label nothin, and it's as cheap as it gets. JMHO
Cheers,
otrpu